[Deiz]

So, I have a Fiio E5 as of about a week ago. I've been fiddling with it, and it's neat - But obviously it has no place in my home rig, and I bought it mainly as a curiosity.

However, I have found a purpose for it. I'd like to know if my math is correct.

To go in order of my signal path, my computer outputs music at about -11 dB (Amarok's ReplayGain script does its best to achieve 89 dB.) and my PCM volume is 0 dB.

Fed to the GS-X, I listen with the HD650s at the 3rd volume setting (Of 24. The first being off.) We're going to assume the DA220's output is 0 dB - Being deep class A, it may end up being hotter than that.

Assuming the 24th position is completely unattenuated - The full two watts per channel with line level input, I listen at -52.5 dB on the amplifier. Add that to the computer's -11 dB and I am being fed a -63.5 dB signal.

Now, on to the fun part: I like to feed my bass's output to the GS-X. To get it to the same level as the computer, I had to turn the volume up to the maximum.

Now, with the introduction of the E5, I'm able to turn the GS-X down by 10 notches - 25 dB. I'd assume that since I'm still at the 14th notch, 11 away from normal listening, that gain has been increased by 52.5 dB, and thusly, the bass signal is -116 dB.

Is this method of calculating sane?

 

[Jo-Vo]

Hello Deiz.

I wonder if you are mixing up different Units of measurement.

Quote:

Originally Posted by Deiz /img/forum/go_quote.gif To go in order of my signal path, my computer outputs music at about -11 dB (Amarok's ReplayGain script does its best to achieve 89 dB.) and my PCM volume is 0 dB.

This should be dBFS.

Quote:

Originally Posted by Deiz /img/forum/go_quote.gif Assuming the 24th position is completely unattenuated - The full two watts per channel with line level input, I listen at -52.5 dB on the amplifier. Add that to the computer's -11 dB and I am being fed a -63.5 dB signal.

I don't understand how you got -52.5 dB from the step of the volume knob your using and I really don't know why this value is negative.
Don't you need values in dBu or dBV or when talking about the level of your headphones in dBSPL?

Sorry for my english...

Regards,
Jonas

 

[eruditass]

Quote:

Originally Posted by Deiz /img/forum/go_quote.gif Is this method of calculating sane?

No.

What point does it serve over using a sound dB meter after the nonlinear headphone response?

 

[Deiz]

Quote:

Originally Posted by Jo-Vo /img/forum/go_quote.gif Hello Deiz. I wonder if you are mixing up different Units of measurement. This should be dBFS. I don't understand how you got -52.5 dB from the step of the volume knob your using and I really don't know why this value is negative. Don't you need values in dBu or dBV or when talking about the level of your headphones in dBSPL? Sorry for my english... Regards, Jonas

The stepped attenuator on my amp has 24 steps, 2.5 dB each. I'm assuming the 24th is unattenuated line level @ 2 WPC.

 

[jjss]

So, I have a Fiio E5 as of about a week ago. I've been fiddling with it, and it's neat - But obviously it has no place in my home rig, and I bought it mainly as a curiosity.

However, I have found a purpose for it. I'd like to know if my math is correct.

To go in order of my signal path, my computer outputs music at about -11 dB (Amarok's ReplayGain script does its best to achieve 89 dB.) and my PCM volume is 0 dB.

Fed to the GS-X, I listen with the HD650s at the 3rd volume setting (Of 24. The first being off.) We're going to assume the DA220's output is 0 dB - Being deep class A, it may end up being hotter than that.

Assuming the 24th position is completely unattenuated - The full two watts per channel with line level input, I listen at -52.5 dB on the amplifier. Add that to the computer's -11 dB and I am being fed a -63.5 dB signal.

Now, on to the fun part: I like to feed my bass's output to the GS-X. To get it to the same level as the computer, I had to turn the volume up to the maximum.

Now, with the introduction of the E5, I'm able to turn the GS-X down by 10 notches - 25 dB. I'd assume that since I'm still at the 14th notch, 11 away from normal listening, that gain has been increased by 52.5 dB, and thusly, the bass signal is -116 dB.

Is this method of calculating sane?

Don't think you can simply arithmetically add these "dB" numbers. Amarok ReplayGain is a kind of loudness normalization in that it looks at a song's integrated LUFS and the digital dBTP and adjust sound level accordingly. Since pure "dB" is a dimensionless quantity it needs to be related to some reference in context, like voltage (dBu / dBV), and in digital domain, a component's internal digital headroom is manufacturer specific and some commonly level is 0dBFS = +24dBu for example. This is clipping voltage in analog term. I think what you're trying to workout is something like a gain structure in a system chain in a mixing / mastering environment.